The Search for Life: Practice Problem Solutions

1. Liquid water, an energy source, and the right chemistry (carbon and other elements).

2. Any two of: Mars (ancient rivers and lakes), Europa and Enceladus (oceans under ice with heat and chemicals), Titan (organic chemistry, methane lakes).

3. A sign, such as a gas in an atmosphere, that could be made by living things.

4. A strong radio signal detected in 1977 that was never heard again and was never explained.

5. Non-living processes could produce the same shapes, and other evidence did not support life.

6. No, only some building blocks have been made. It is called the origin-of-life problem.

7. They hold a range of views; the Bible neither promises nor rules out life elsewhere, and many Christians would not find it threatening.